Rotator Cuff Injury

Aka: Rotator Cuff Injury, Rotator Cuff Syndrome

1. Epidemiology
   1. Rotator cuff is responsible for most Shoulder Pain
   2. Age of onset typically over 40 years old
2. Anatomy
   1. See Shoulder Anatomy
   2. Rotator cuff fuses near humeral tuberosity
   3. Image
      1. 
3. Risk Factors: Predisposition for injury increases with advancing age
   1. Trauma at tendons (especially supraspinatus)
   2. Secondary inflammation
   3. Thickening at subacromial bursa
4. Types
   1. Rotator Cuff Tendonitis
   2. Rotator Cuff Rupture
   3. Rotator Cuff Calcification
5. Symptoms
   1. Characteristics
      1. Lateral arm without radiation beyond elbow
      2. Associated with arm weakness
   2. Timing
      1. Night pain interferes with sleep
   3. Provocative
      1. Exacerbated by throwing motion
      2. Overhead work
6. Signs
   1. Painful arc
   2. Positive Shoulder Impingement Signs
7. Differential Diagnosis
   1. See Shoulder Pain
8. Imaging
   1. Shoulder XRay (first-line)
      1. Calcific Tendonitis
      2. Hook Acromion (See Acromion XRay Findings)
      3. Bone cysts or sclerosis within humeral head
   2. Shoulder Ultrasound
      1. Evaluates Rotator Cuff Tears (esp. full thickness) well
      2. Best in patients older than age 40 years old (tend to have full thickness tears)
      3. Rotator cuff is nearly identical appearance as T2w MRI (with an inverse/negative of brightness/echogenicity)
   3. Shoulder MRI
      1. Best at evaluating differential diagnosis (e.g Labral Tear)
      2. Best in patients younger than age 40 years (tend to have partial tears and other pathology)
9. Management: Sample Protocol
   1. See specific rotator cuff conditions
      1. Rotator Cuff Tendonitis
      2. Rotator Cuff Rupture
      3. Rotator Cuff Calcification
   2. Initial Visit
      1. Evaluate for serious Traumatic Injury
         1. Careful Shoulder Exam
         2. Shoulder XRay
      2. Start Conservative Therapy
         1. Modify activity (e.g. Avoid overhead work, avoid heavy lifting)
         2. Start physical therapy and encourage early Shoulder mobilization
         3. NSAIDs
   3. Next Visit (at 3 weeks from onset)
      1. Consider Subacromial Corticosteroid Injection for severe or refractory symptoms
      2. Adjust activity restrictions
      3. Consider MRI and Orthopedic Consultation if suspect large Rotator Cuff Tear
         1. Traumatic Injury
         2. Severe pain and weakness
         3. Positive Drop Arm Test
         4. Weakness on Empty Cans Testing (esp. if persists despite injection)
   4. Next Visit (at 6 to 12 weeks from onset)
      1. Adjust activity restrictions
      2. Consider MRI and Orthopedic Consultation
         1. Suspected partial Rotator Cuff Tear and persistent symptoms
   5. Next visit (at 6 months from onset)
      1. Reevaluate Shoulder function and pain
      2. Consider permanent change in job duties if recurrent reinjury
      3. Consider repeat Subacromial Corticosteroid Injection
      4. Consider MRI and referral for persistent symptoms (esp. if Hook Acromion)
      5. Consider advanced measures (typically by sports medicine)
         1. Extracorporeal shock wave therapy
         2. Platelet-rich plasma injection
         3. Dextrose prolotherapy
10. References
    1. Burbank (2008) Am Fam Physician 77:493-7 [PubMed]
    2. Kane (2019) Am Fam Physician 100(3): 147-57 [PubMed]
    3. Mantone (2000) Orthop Clin North Am 31:295-311 [PubMed]